Suppression of magnon excitations in Co2MnSi Heusler alloy by Nd doping

We have investigated the effect of Nd doping on the transport and magnetic properties of Co2MnSi. The substitution of 1.25 at. % Nd for Co results in a single L2(1) phase with a thin layer of Nd enriched phase grain boundaries. However, from resistivity measurements at low temperatures, the suppression of electron-magnon scattering was observed in the alloy with Nd enriched phase. The magnetic moment of Co2MnSi was 5.01 mu(B), whereas that of Co1.95Nd0.05MnSi is 5.35 mu(B), which indicates that the Nd rich phase couples ferromagnetically with the Co1.95Nd0.05MnSi phase. Moreover, point contact Andreev reflection measurements at 4.2 K have shown almost the same spin polarization with (P=0.59) and without Nd doping (P=0.58), indicating that Nd enrichment in the grain boundary does not hamper the spin polarization, but prevents the temperature dependent decay of transport properties.